Metal oxide semiconductor field effect transistor (MOSFET) structures are used in many different analog circuits through the use of complimentary metal oxide semiconductor (CMOS) technology. For example, high speed/low power circuitry in low voltage applications requires reliable analog transmission gate structures. Analog transmission gates are used in digital CMOS circuit design as switches that selectively pass high level and low level logic signals.
Referring to FIG. 1, an exemplary transmission gate 10 includes an n-channel MOS (NMOS) transistor 12 and a p-channel MOS (PMOS) transistor 14. The NMOS transistor 12 and PMOS transistor 14 are connected in parallel and share a common source 16 and a common drain 18. A gate 20 of the NMOS transistor 12 is coupled to a clock signal (CLK) and a gate 22 of the PMOS transistor is coupled to an inverted clock signal (CLKbar). Conventionally, a body 24, or bulk, of the NMOS transistor 12 is connected to a ground potential and a body 26 of the PMOS transistor 14 is supplied with a supply voltage (VDD).
The transmission gate 10 receives an input voltage (Vin) at the common source 16 and transmits an output signal (Vout) when activated. During operation at low voltages, the bodies, 24, 26 may experience a different potential than the common source 16.